Tape head and system having asymmetrical construction

ABSTRACT

An apparatus according to one embodiment includes a module having a tape bearing surface, a first edge, and a second edge, where a tape tenting region extends from the first edge toward the second edge, the first edge being a first end of the tape tenting region, a second end of the tape tenting region being positioned between the first and second edges. The apparatus includes a guide positioned relative to the first edge for inducing tenting of a moving magnetic recording tape and a transducer positioned in the tape tenting region. In addition, the module has a wear coating on a media facing side of the transducer, where a peak height is defined between the peak of tenting and an upper surface of the coating. The thickness of the wear coating is in a range of between about 0.5 and about 3 times the peak height.

BACKGROUND

The present invention relates to data storage systems, and moreparticularly, this invention relates to magnetic tape recording, moreparticularly, to an asymmetrical tape head and/or tape recording systemwith asymmetrical wrap angles.

In magnetic storage systems, magnetic transducers read data from andwrite data onto magnetic recording media. Data is written on themagnetic recording media by moving a magnetic recording transducer to aposition over the media where the data is to be stored. The magneticrecording transducer then generates a magnetic field, which encodes thedata into the magnetic media. Data is read from the media by similarlypositioning the magnetic read transducer and then sensing the magneticfield of the magnetic media. Read and write operations may beindependently synchronized with the movement of the media to ensure thatthe data can be read from and written to the desired location on themedia.

An important and continuing goal in the data storage industry is that ofincreasing the density of data stored on a medium. For tape storagesystems, that goal has led to increasing the track and linear bitdensity on recording tape, and decreasing the thickness of the magnetictape medium. However, the development of small footprint, higherperformance tape drive systems has created various problems in thedesign of a tape head assembly for use in such systems.

In a tape drive system, the drive moves the magnetic tape over thesurface of the tape head at high speed. Usually the tape head isdesigned to minimize the spacing between the head and the tape. Thespacing between the magnetic head and the magnetic tape is crucial andso goals in these systems are to have the recording gaps of thetransducers, which are the source of the magnetic recording flux in nearcontact with the tape to effect writing sharp transitions, and to havethe read elements in near contact with the tape to provide effectivecoupling of the magnetic field from the tape to the read elements.

SUMMARY

An apparatus according to one embodiment includes a module having a tapebearing surface, a first edge, and a second edge, where a tape tentingregion of the tape bearing surface extends from the first edge along thetape bearing surface toward the second edge, the first edge of the tapebearing surface being a first end of the tape tenting region, a secondend of the tape tenting region being positioned between the first andsecond edges. The apparatus includes a guide positioned relative to thefirst edge for inducing tenting of a moving magnetic recording tape anda transducer positioned in the tape tenting region. The location of thetenting is above an entirety of the tape tenting region, where thesecond end of the tape tenting region is located at a location where thetenting terminates at a point of closest approach of the tape to thetape bearing surface after a peak of the tenting. In addition, themodule has a wear coating on a media facing side of the transducer,where a peak height is defined between the peak of tenting and an uppersurface of the coating. The thickness of the wear coating is in a rangeof between about 0.5 and about 3 times the peak height.

According to another embodiment, a method includes determining a firstdistance from a sensor to a first edge closest thereto, where the sensoris positioned between a lower shield and the first edge, selecting afirst wrap angle based on the first distance for inducing tenting of amoving magnetic recording tape in a region above the sensor, determininga second distance from a second edge to the sensor, and selecting asecond wrap angle based on the determined_(—) second distance foraffecting or not affecting the tenting of a moving magnetic recordingtape in the region above the sensor.

According to yet another embodiment, a method includes running amagnetic recording tape over an edge proximate to a sensor of a module,detecting magnetic fields from the magnetic recording tape, andselecting a wrap angle to provide about a predefined height of tentingof the magnetic recording tape above the sensor as determined using thedetected magnetic fields.

According to yet another embodiment, a computer-implemented methodincludes receiving a measurement of a distance from a first edge to asensor, receiving a predefined height of tenting of a magnetic recordingtape above the sensor, and calculating a wrap angle to create thepredefined height of tenting when the magnetic recording tape passesover the first edge in a direction of tape travel.

Any of these embodiments may be implemented in a magnetic data storagesystem such as a tape drive system, which may include a magnetic head, adrive mechanism for moving a magnetic medium (e.g., recording tape) overthe magnetic head, and a controller electrically coupled to the magnetichead.

Other aspects and embodiments of the present invention will becomeapparent from the following detailed description, which, when taken inconjunction with the drawings, illustrate by way of example theprinciples of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a schematic diagram of a simplified tape drive systemaccording to one embodiment.

FIG. 1B is a schematic diagram of a tape cartridge according to oneembodiment.

FIG. 2 illustrates a side view of a flat-lapped, bi-directional,two-module magnetic tape head according to one embodiment.

FIG. 2A is a tape bearing surface view taken from Line 2A of FIG. 2.

FIG. 2B is a detailed view taken from Circle 2B of FIG. 2A.

FIG. 2C is a detailed view of a partial tape bearing surface of a pairof modules.

FIG. 3 is a partial tape bearing surface view of a magnetic head havinga write-read-write configuration.

FIG. 4 is a partial tape bearing surface view of a magnetic head havinga read-write-read configuration.

FIG. 5 is a side view of a magnetic tape head with three modulesaccording to one embodiment where the modules all generally lie alongabout parallel planes.

FIG. 6 is a side view of a magnetic tape head with three modules in atangent (angled) configuration.

FIGS. 7A-7C are schematics depicting the principles of tape tenting.

FIG. 8A is a side view of a magnetic tape head according to oneembodiment.

FIG. 8B is a detailed view of circle 8B of FIG. 8A according to oneembodiment.

FIG. 9 is a side view of a magnetic tape head according to oneembodiment.

FIG. 10A is a side view of a magnetic tape head according to oneembodiment.

FIG. 10B is a detailed side view of a magnetic tape head according toone embodiment.

FIG. 11A-11B are graphic examples of Finite Element Modeling (FEM)according to various embodiments

FIG. 12 is a flow chart of a method according to one embodiment.

FIG. 13 is a flow chart of a method according to one embodiment.

FIG. 14 is a flow chart of a method according to one embodiment.

DETAILED DESCRIPTION

The following description is made for the purpose of illustrating thegeneral principles of the present invention and is not meant to limitthe inventive concepts claimed herein. Further, particular featuresdescribed herein can be used in combination with other describedfeatures in each of the various possible combinations and permutations.

Unless otherwise specifically defined herein, all terms are to be giventheir broadest possible interpretation including meanings implied fromthe specification as well as meanings understood by those skilled in theart and/or as defined in dictionaries, treatises, etc.

It must also be noted that, as used in the specification and theappended claims, the singular forms “a,” “an” and “the” include pluralreferents unless otherwise specified.

The following description discloses several preferred embodiments ofmagnetic storage systems, as well as operation and/or component partsthereof.

In one general embodiment, an apparatus includes a module having a tapebearing surface, a first edge, and a second edge. A first tape tentingregion extends from the first edge along the tape bearing surface towardthe second edge. A transducer is located in a thin film region of themodule. A distance from the first edge to the transducer is less than adistance from the second edge to the transducer. The transducer ispositioned in the first tape tenting region.

In one general embodiment, an apparatus includes a module having a tapebearing surface, a first edge, and a second edge. A first tape tentingregion extends from the first edge along the tape bearing surface towardthe second edge. A first guide is positioned relative to the first edgefor inducing tenting of a moving magnetic recording tape. The locationof the tenting is above the first tape tenting region. A second guide ispositioned relative to the second edge for inducing tenting of themoving magnetic recording tape. The first guide is positioned relativeto the first edge to create a first wrap angle and the second guide ispositioned relative to the second edge to create a second wrap angle.The first wrap angle is not the same as the second wrap angle. Atransducer is positioned in the first tape tenting region.

FIG. 1A illustrates a simplified tape drive 100 of a tape-based datastorage system, which may be employed in the context of the presentinvention. While one specific implementation of a tape drive is shown inFIG. 1A, it should be noted that the embodiments described herein may beimplemented in the context of any type of tape drive system.

As shown, a tape supply cartridge 120 and a take-up reel 121 areprovided to support a tape 122. One or more of the reels may form partof a removable cartridge and are not necessarily part of the system 100.The tape drive, such as that illustrated in FIG. 1A, may further includedrive motor(s) to drive the tape supply cartridge 120 and the take-upreel 121 to move the tape 122 over a tape head 126 of any type. Suchhead may include an array of readers, writers, or both.

Guides 125 guide the tape 122 across the tape head 126. Such tape head126 is in turn coupled to a controller 128 via a cable 130. Thecontroller 128, may be or include a processor and/or any logic forcontrolling any subsystem of the drive 100. For example, the controller128 typically controls head functions such as servo following, datawriting, data reading, etc. The controller 128 may include at least oneservo channel and at least one data channel, each of which include dataflow processing logic configured to process and/or store information tobe written to and/or read from the tape 122. The controller 128 mayoperate under logic known in the art, as well as any logic disclosedherein, and thus may be considered as a processor for any of thedescriptions of tape drives included herein, in various embodiments. Thecontroller 128 may be coupled to a memory 136 of any known type, whichmay store instructions executable by the controller 128. Moreover, thecontroller 128 may be configured and/or programmable to perform orcontrol some or all of the methodology presented herein. Thus, thecontroller 128 may be considered to be configured to perform variousoperations by way of logic programmed into one or more chips, modules,and/or blocks; software, firmware, and/or other instructions beingavailable to one or more processors; etc., and combinations thereof.

The cable 130 may include read/write circuits to transmit data to thehead 126 to be recorded on the tape 122 and to receive data read by thehead 126 from the tape 122. An actuator 132 controls position of thehead 126 relative to the tape 122.

An interface 134 may also be provided for communication between the tapedrive 100 and a host (internal or external) to send and receive the dataand for controlling the operation of the tape drive 100 andcommunicating the status of the tape drive 100 to the host, all as willbe understood by those of skill in the art.

FIG. 1B illustrates an exemplary tape cartridge 150 according to oneembodiment. Such tape cartridge 150 may be used with a system such asthat shown in FIG. 1A. As shown, the tape cartridge 150 includes ahousing 152, a tape 122 in the housing 152, and a nonvolatile memory 156coupled to the housing 152. In some approaches, the nonvolatile memory156 may be embedded inside the housing 152, as shown in FIG. 1B. In moreapproaches, the nonvolatile memory 156 may be attached to the inside oroutside of the housing 152 without modification of the housing 152. Forexample, the nonvolatile memory may be embedded in a self-adhesive label154. In one preferred embodiment, the nonvolatile memory 156 may be aFlash memory device, ROM device, etc., embedded into or coupled to theinside or outside of the tape cartridge 150. The nonvolatile memory isaccessible by the tape drive and the tape operating software (the driversoftware), and/or another device.

By way of example, FIG. 2 illustrates a side view of a flat-lapped,bi-directional, two-module magnetic tape head 200 which may beimplemented in the context of the present invention. As shown, the headincludes a pair of bases 202, each equipped with a module 204, and fixedat a small angle a with respect to each other. The bases may be“U-beams” that are adhesively coupled together. Each module 204 includesa substrate 204A and a closure 204B with a thin film portion, commonlyreferred to as a “gap” in which the readers and/or writers 206 areformed. In use, a tape 208 is moved over the modules 204 along a media(tape) bearing surface 209 in the manner shown for reading and writingdata on the tape 208 using the readers and writers.

The substrates 204A are typically constructed of a wear resistantmaterial, such as a ceramic. The closures 204B may be made of the sameor similar ceramic as the substrates 204A.

The readers and writers may be arranged in a piggyback or mergedconfiguration. An illustrative piggybacked configuration comprises a(magnetically inductive) writer transducer on top of (or below) a(magnetically shielded) reader transducer (e.g., a magnetoresistivereader, etc.), wherein the poles of the writer and the shields of thereader are generally separated. An illustrative merged configurationcomprises one reader shield in the same physical layer as one writerpole (hence, “merged”). The readers and writers may also be arranged inan interleaved configuration. Alternatively, each array of channels maybe readers or writers only. Any of these arrays may contain one or moreservo track readers for reading servo data on the medium.

FIG. 2A illustrates the tape bearing surface 209 of one of the modules204 taken from Line 2A of FIG. 2. A representative tape 208 is shown indashed lines. The module 204 is preferably long enough to be able tosupport the tape as the head steps between data bands.

In this example, the tape 208 includes 4 to 32 data bands, e.g., with 16data bands and 17 servo tracks 210, as shown in FIG. 2A on a one-halfinch wide tape 208. The data bands are defined between servo tracks 210.Each data band may include a number of data tracks, for example 1024data tracks (not shown). During read/write operations, the readersand/or writers 206 are positioned to specific track positions within oneof the data bands. Outer readers, sometimes called servo readers, readthe servo tracks 210. The servo signals are in turn used to keep thereaders and/or writers 206 aligned with a particular set of tracksduring the read/write operations.

FIG. 2B depicts a plurality of readers and/or writers 206 formed in agap 218 on the module 204 in Circle 2B of FIG. 2A. As shown, the arrayof readers and writers 206 includes, for example, 16 writers 214, 16readers 216 and two servo readers 212, though the number of elements mayvary. Illustrative embodiments include 8, 16, 32, 40, and 64 activereaders and/or writers 206 per array, and alternatively interleaveddesigns having odd numbers of reader or writers such as 17, 25, 33, etc.An illustrative embodiment includes 32 readers per array and/or 32writers per array, where the actual number of transducer elements couldbe greater, e.g., 33, 34, etc. This allows the tape to travel moreslowly, thereby reducing speed-induced tracking and mechanicaldifficulties and/or execute fewer “wraps” to fill or read the tape.While the readers and writers may be arranged in a piggybackconfiguration as shown in FIG. 2B, the readers 216 and writers 214 mayalso be arranged in an interleaved configuration. Alternatively, eacharray of readers and/or writers 206 may be readers or writers only, andthe arrays may contain one or more servo readers 212. As noted byconsidering FIGS. 2 and 2A-B together, each module 204 may include acomplementary set of readers and/or writers 206 for such things asbi-directional reading and writing, read-while-write capability,backward compatibility, etc.

FIG. 2C shows a partial tape bearing surface view of complementarymodules of a magnetic tape head 200 according to one embodiment. In thisembodiment, each module has a plurality of read/write (R/W) pairs in apiggyback configuration formed on a common substrate 204A and anoptional electrically insulative layer 236. The writers, exemplified bythe write transducer 214 and the readers, exemplified by the readtransducer 216, are aligned parallel to an intended direction of travelof a tape medium thereacross to form an R/W pair, exemplified by the R/Wpair 222. Note that the intended direction of tape travel is sometimesreferred to herein as the direction of tape travel, and such terms maybe used interchangeably. Such direction of tape travel may be inferredfrom the design of the system, e.g., by examining the guides; observingthe actual direction of tape travel relative to the reference point;etc. Moreover, in a system operable for bi-direction reading and/orwriting, the direction of tape travel in both directions is typicallyparallel and thus both directions may be considered equivalent to eachother.

Several R/W pairs 222 may be present, such as 8, 16, 32 pairs, etc. TheR/W pairs 222 as shown are linearly aligned in a direction generallyperpendicular to a direction of tape travel thereacross. However, thepairs may also be aligned diagonally, etc. Servo readers 212 arepositioned on the outside of the array of R/W pairs, the function ofwhich is well known.

Generally, the magnetic tape medium moves in either a forward or reversedirection as indicated by arrow 220. The magnetic tape medium and headassembly 200 operate in a transducing relationship in the mannerwell-known in the art. The piggybacked MR head assembly 200 includes twothin-film modules 224 and 226 of generally identical construction.

Modules 224 and 226 are joined together with a space present betweenclosures 204B thereof (partially shown) to form a single physical unitto provide read-while-write capability by activating the writer of theleading module and reader of the trailing module aligned with the writerof the leading module parallel to the direction of tape travel relativethereto. When a module 224, 226 of a piggyback head 200 is constructed,layers are formed in the gap 218 created above an electricallyconductive substrate 204A (partially shown), e.g., of AlTiC, ingenerally the following order for the R/W pairs 222: an insulating layer236, a first shield 232 typically of an iron alloy such as NiFe (-),cobalt zirconium tantalum (CZT) or Al—Fe—Si (Sendust), a sensor 234 forsensing a data track on a magnetic medium, a second shield 238 typicallyof a nickel-iron alloy (e.g., ˜80/20 at % NiFe, also known aspermalloy), first and second writer pole tips 228, 230, and a coil (notshown). The sensor may be of any known type, including those based onMR, GMR, AMR, tunneling magnetoresistance (TMR), etc.

The first and second writer poles 228, 230 may be fabricated from highmagnetic moment materials such as ˜45/55 NiFe. Note that these materialsare provided by way of example only, and other materials may be used.Additional layers such as insulation between the shields and/or poletips and an insulation layer surrounding the sensor may be present.Illustrative materials for the insulation include alumina and otheroxides, insulative polymers, etc.

The configuration of the tape head 126 according to one embodimentincludes multiple modules, preferably three or more. In awrite-read-write (W-R-W) head, outer modules for writing flank one ormore inner modules for reading. Referring to FIG. 3, depicting a W-R-Wconfiguration, the outer modules 252, 256 each include one or morearrays of writers 260. The inner module 254 of FIG. 3 includes one ormore arrays of readers 258 in a similar configuration. Variations of amulti-module head include a R-W-R head (FIG. 4), a R-R-W head, a W-W-Rhead, etc. In yet other variations, one or more of the modules may haveread/write pairs of transducers. Moreover, more than three modules maybe present. In further approaches, two outer modules may flank two ormore inner modules, e.g., in a W-R-R-W, a R-W-W-R arrangement, etc. Forsimplicity, a W-R-W head is used primarily herein to exemplifyembodiments of the present invention. One skilled in the art apprisedwith the teachings herein will appreciate how permutations of thepresent invention would apply to configurations other than a W-R-Wconfiguration.

FIG. 5 illustrates a magnetic head 126 according to one embodiment ofthe present invention that includes first, second and third modules 302,304, 306 each having a tape bearing surface 308, 310, 312 respectively,which may be flat, contoured, etc. Note that while the term “tapebearing surface” appears to imply that the surface facing the tape 315is in physical contact with the tape bearing surface, this is notnecessarily the case. Rather, only a portion of the tape may be incontact with the tape bearing surface, constantly or intermittently,with other portions of the tape riding (or “flying”) above the tapebearing surface on a layer of air, sometimes referred to as an “airbearing”. The first module 302 will be referred to as the “leading”module as it is the first module encountered by the tape in a threemodule design for tape moving in the indicated direction. The thirdmodule 306 will be referred to as the “trailing” module. The trailingmodule follows the middle module and is the last module seen by the tapein a three module design. The leading and trailing modules 302, 306 arereferred to collectively as outer modules. Also note that the outermodules 302, 306 will alternate as leading modules, depending on thedirection of travel of the tape 315.

In one embodiment, the tape bearing surfaces 308, 310, 312 of the first,second and third modules 302, 304, 306 lie on about parallel planes(which is meant to include parallel and nearly parallel planes, e.g.,between parallel and tangential as in FIG. 6), and the tape bearingsurface 310 of the second module 304 is above the tape bearing surfaces308, 312 of the first and third modules 302, 306. As described below,this has the effect of creating the desired wrap angle of the taperelative to the tape bearing surface 310 of the second module 304.

Where the tape bearing surfaces 308, 310, 312 lie along parallel ornearly parallel yet offset planes, intuitively, the tape should peel offof the tape bearing surface 308 of the leading module 302. However, thevacuum created by the skiving edge 318 of the leading module 302 hasbeen found by experimentation to be sufficient to keep the tape adheredto the tape bearing surface 308 of the leading module 302. The trailingedge 320 of the leading module 302 (the end from which the tape leavesthe leading module 302) is the approximate reference point which definesthe wrap angle over the tape bearing surface 310 of the second module304. The tape stays in close proximity to the tape bearing surface untilclose to the trailing edge 320 of the leading module 302. Accordingly,read and/or write elements 322 may be located near the trailing edges ofthe outer modules 302, 306. These embodiments are particularly adaptedfor write-read-write applications.

A benefit of this and other embodiments described herein is that,because the outer modules 302, 306 are fixed at a determined offset fromthe second module 304, the inner wrap angle is fixed when the modules302, 304, 306 are coupled together or are otherwise fixed into a head.The inner wrap angle is approximately tan⁻¹(δ/W) where δ is the heightdifference between the planes of the tape bearing surfaces 308, 310 andW is the width between the opposing ends of the tape bearing surfaces308, 310. An illustrative inner wrap angle is in a range of about 0.3°to about 1.1°, though can be any angle required by the design.

Beneficially, the inner wrap angle on the side of the module 304receiving the tape (leading edge) will be larger than the inner wrapangle on the trailing edge, as the tape 315 rides above the trailingmodule 306. This difference is generally beneficial as a smaller tendsto oppose what has heretofore been a steeper exiting effective wrapangle.

Note that the tape bearing surfaces 308, 312 of the outer modules 302,306 are positioned to achieve a negative wrap angle at the trailing edge320 of the leading module 302. This is generally beneficial in helpingto reduce friction due to contact with the trailing edge 320, providedthat proper consideration is given to the location of the crowbar regionthat forms in the tape where it peels off the head. This negative wrapangle also reduces flutter and scrubbing damage to the elements on theleading module 302. Further, at the trailing module 306, the tape 315flies over the tape bearing surface 312 so there is virtually no wear onthe elements when tape is moving in this direction. Particularly, thetape 315 entrains air and so will not significantly ride on the tapebearing surface 312 of the third module 306 (some contact may occur).This is permissible, because the leading module 302 is writing while thetrailing module 306 is idle.

Writing and reading functions are performed by different modules at anygiven time. In one embodiment, the second module 304 includes aplurality of data and optional servo readers 331 and no writers. Thefirst and third modules 302, 306 include a plurality of writers 322 andno data readers, with the exception that the outer modules 302, 306 mayinclude optional servo readers. The servo readers may be used toposition the head during reading and/or writing operations. The servoreader(s) on each module are typically located towards the end of thearray of readers or writers.

By having only readers or side by side writers and servo readers in thegap between the substrate and closure, the gap length can besubstantially reduced. Typical heads have piggybacked readers andwriters, where the writer is formed above each reader. A typical gap is20-35 microns. However, irregularities on the tape may tend to droopinto the gap and create gap erosion. Thus, the smaller the gap is thebetter. The smaller gap enabled herein exhibits fewer wear relatedproblems.

In some embodiments, the second module 304 has a closure, while thefirst and third modules 302, 306 do not have a closure. Where there isno closure, preferably a hard coating is added to the module. Onepreferred coating is diamond-like carbon (DLC).

In the embodiment shown in FIG. 5, the first, second, and third modules302, 304, 306 each have a closure 332, 334, 336, which extends the tapebearing surface of the associated module, thereby effectivelypositioning the read/write elements away from the edge of the tapebearing surface. The closure 332 on the second module 304 can be aceramic closure of a type typically found on tape heads. The closures334, 336 of the first and third modules 302, 306, however, may beshorter than the closure 332 of the second module 304 as measuredparallel to a direction of tape travel over the respective module. Thisenables positioning the modules closer together. One way to produceshorter closures 334, 336 is to lap the standard ceramic closures of thesecond module 304 an additional amount. Another way is to plate ordeposit thin film closures above the elements during thin filmprocessing. For example, a thin film closure of a hard material such asSendust or nickel-iron alloy (e.g., 45/55) can be formed on the module.

With reduced-thickness ceramic or thin film closures 334, 336 or noclosures on the outer modules 302, 306, the write-to-read gap spacingcan be reduced to less than about 1 mm, e.g., about 0.75 mm, or 50% lessthan commonly-used LTO tape head spacing. The open space between themodules 302, 304, 306 can still be set to approximately 0.5 to 0.6 mm,which in some embodiments is ideal for stabilizing tape motion over thesecond module 304.

Depending on tape tension and bending stiffness, it may be desirable toangle the tape bearing surfaces of the outer modules relative to thetape bearing surface of the second module. FIG. 6 illustrates anembodiment where the modules 302, 304, 306 are in a tangent or nearlytangent (angled) configuration. Particularly, the tape bearing surfacesof the outer modules 302, 306 are about parallel to the tape at thedesired wrap angle of the second module 304. In other words, the planesof the tape bearing surfaces 308, 312 of the outer modules 302, 306 areoriented at about the desired wrap angle of the tape 315 relative to thesecond module 304. The tape will also pop off of the trailing module 306in this embodiment, thereby reducing wear on the elements in thetrailing module 306. These embodiments are particularly useful forwrite-read-write applications. Additional aspects of these embodimentsare similar to those given above.

Typically, the tape wrap angles may be set about midway between theembodiments shown in FIGS. 5 and 6.

Additional aspects of the embodiments shown in FIG. 6 are similar tothose given above.

A 32 channel version of a multi-module head 126 may use cables 350having leads on the same or smaller pitch as current 16 channelpiggyback LTO modules, or alternatively the connections on the modulemay be organ-keyboarded for a 50% reduction in cable span. Over-under,writing pair unshielded cables may be used for the writers, which mayhave integrated servo readers.

The outer wrap angles may be set in the drive, such as by guides of anytype known in the art, such as adjustable rollers, slides, etc. oralternatively by outriggers, which are integral to the head. Forexample, rollers having an offset axis may be used to set the wrapangles. The offset axis creates an orbital arc of rotation, allowingprecise alignment of the wrap angle.

To assemble any of the embodiments described above, conventional u-beamassembly can be used. Accordingly, the mass of the resultant head may bemaintained or even reduced relative to heads of previous generations. Inother approaches, the modules may be constructed as a unitary body.Those skilled in the art, armed with the present teachings, willappreciate that other known methods of manufacturing such heads may beadapted for use in constructing such heads. Moreover, unless otherwisespecified, processes and materials of types known in the art may beadapted for use in various embodiments in conformance with the teachingsherein, as would become apparent to one skilled in the art upon readingthe present disclosure.

Conventionally, limitations on areal density are imposed by loss ofsignal quality due to increase in head-media spacing resulting from headwear, or from deposits or other buildup on the head surface. A methodused by the industry to counter the effects of head wear includespre-recessing and coating the magnetic head. However, pre-recession andcoating increase magnetic spacing between the tape and the surface ofthe sensor and may limit achievable recording linear density.

A longer tape bearing surface between the edges of a module may enableminimal tape-to-head spacing may improve resolution and signal output.Specifically, a longer tape bearing surface creates a middle region ofthe tape bearing surface for the tape to couple with between regions oftenting created by the tape at each edge of the module. However, in TMRheads, minimal spacing between tape and the tape bearing surface of thesensor may result in shorting of the sensor by the moving tape.Unfortunately, shorting of the TMR sensor has the capability to render aTMR sensor partially to completely non-functional.

Particularly, defects in the magnetic medium may cause shorting acrossthe sensor. Conventionally, pre-recessed sensors with very hard coatingson the media bearing surfaces help mitigate wear and shorting due todefects in the magnetic medium passing over the sensor. However, undersevere conditions, such as large defects embedded in the media, shortingmay still occur in these heads. Moreover, coatings may be susceptible towear by the tape and thus become less protective over time.

Methods such as pre-recession of the recording gap and/or coating on thetape bearing surface may also be used to control head-tape spacing.However, neither of these methods provide a way to tailor the spacingaccording to measured head geometry for each head. In addition, when thefabrication processes of the module are complete, there are nopreviously-known methods to make adjustments to the spacing between thehead and tape. Accordingly, because the spacing in conventional headsmay be at a minimal spacing, the shorting problem of TMR sensors hasbeen a pervasive barrier to the introduction of TMR to tape recording.

Various embodiments described herein provide, along with heads havingtransducers such as such as sensors (e.g., data sensors, servo sensors,Hall effect sensors, etc.) and/or write transducers (writer) positionedin the tape tenting region, methods to set the fly height of a tapeabove the sensors precisely to about a predetermined value that may beindependent of variations of head geometry. Furthermore, it is desirableto have a certain approximate predefined spacing between the tapebearing surface of the sensor and the tape because error rate, bit errorrate, resolution, and channel parameters are affected by this spacing.

Moreover, manufacturing processes that define the edge of the tapebearing surface near the sensor are subject to variation. In otherwords, the distance from the edge to the sensor may be controlled within10 μm in some embodiments which may translate to a variation in spacingbetween the sensor and tape of the order of a few nanometers. Thus,despite the variable distances of the sensor to the edge closest theretofrom head to head, the total spacing between the transducer and the tapecan be controlled to a consistent spacing by adjusting the wrap angle.Furthermore, various embodiments described herein include a modulearranged asymmetrically on a tape head.

FIGS. 7A-7C illustrate the principles of tape tenting. FIG. 7A shows amodule 700 having an upper tape bearing surface 702 extending betweenopposite edges 704, 706. A stationary tape 708 is shown wrapping aroundthe edges 704, 706. As shown, the bending stiffness of the tape 708lifts the tape off of the tape bearing surface 702. Tape tension tendsto flatten the tape profile, as shown in FIG. 7A. Where tape tension isminimal, the curvature of the tape is more parabolic than shown.

FIG. 7B depicts the tape 708 in motion. The leading edge, i.e., thefirst edge the tape encounters when moving, may serve to skive air fromthe tape, thereby creating a subambient air pressure between the tape708 and the tape bearing surface 702. In FIG. 7B, the leading edge isthe left edge and the right edge is the trailing edge when the tape ismoving left to right. As a result, atmospheric pressure above the tapeurges the tape toward the tape bearing surface 702, thereby creatingtape tenting proximate each of the edges. The tape bending stiffnessresists the effect of the atmospheric pressure, thereby causing the tapetenting proximate both the leading and trailing edges. Modeling predictsthat the two tents are very similar in shape.

FIG. 7C depicts how the subambient pressure urges the tape 708 towardthe tape bearing surface 702 even when a trailing guide 710 ispositioned above the plane of the tape bearing surface.

The heads depicted in the FIGS. discussed above may be constructed tomitigate the occurrence of shorting due to tape defects by inducing tapetenting above the transducers using the teachings presented herein.

Moreover, the magnetic transducer(s) in any of the embodiments describedherein may be sensors (e.g., data sensors, servo sensors, Hall effectsensors, etc.) and/or write transducers (writer). While much of thefollowing description refers to a sensor being present in the tapetenting region, this is done by way of example only, and any type oftransducer may be used in any of the embodiments in place of thedescribed sensor.

The following description describes various embodiments with referenceto figures. Note that the figures are not drawn to scale, but ratherfeatures may have been exaggerated to help exemplify the descriptionsherein.

FIGS. 8A-8B depicts an apparatus 800 in accordance with one embodiment.As an option, the present apparatus 800 may be implemented inconjunction with features from any other embodiment listed herein, suchas those described with reference to the other FIGS. Of course, however,such an apparatus 800 and others presented herein may be used in variousapplications and/or in permutations which may or may not be specificallydescribed in the illustrative embodiments listed herein. Further, theapparatus 800 presented herein may be used in any desired environment.

In the embodiment of apparatus 800, the module 801 includes a tapebearing surface 808, a first edge 806, and a second edge 804.

Looking to FIG. 8A-8B, the module 801 preferably includes a thin filmregion 814 and a CPP sensor 809 (e.g. such as a TMR sensor, GMR sensor,etc. of a type known in the art) that are positioned between the tapesupport surfaces 822, 824.

According to some embodiments, the sensor 809 may be configured as adata sensor for reading data tracks of a magnetic medium. In someapproaches, the apparatus 800 includes one or more arrays of such datasensors.

According to other embodiments, the sensor 809 may be configured as aservo pattern reading sensor of a servo reader. For example, the sensor809 may be configured as a servo pattern reading sensor where apparatus800 includes one or more arrays of data sensors and/or writers and oneor more servo pattern reading sensors for reading servo data on amedium.

Looking to FIG. 8A-8B, the thin film region 814 may have a first shield819 and a second shield 820. In addition, the second shield 820 may bepositioned proximate to the first edge 806. A CPP sensor 809 (e.g. suchas a TMR sensor, GMR sensor, etc. of a type known in the art) ispositioned between the first and second shields 819, 820. As would beappreciated by one skilled in the art, the first and second shields 819,820 preferably provide magnetic shielding for the CPP sensor 809. Thus,one or both of the shields 819, 820 may desirably include a magneticmaterial of a type known in the art.

Furthermore, in one embodiment of apparatus 800, the sensor 809 in thethin film region 814 of the module 801 may have a reference layer 815.Particularly, as shown in FIG. 8B, the active TMR region of the sensor809 includes a tunnel barrier layer 812 as the spacer layer 812positioned between the free layer 816 and the reference layer 815 e.g.,of conventional construction. According to various embodiments, the freelayer 816, the tunnel barrier layer 812 and/or the reference layer 815may include construction parameters, e.g., materials, dimensions,properties, etc., according to any of the embodiments described herein,and/or conventional construction parameters, depending on the desiredembodiment. Illustrative materials for the tunnel barrier layer 812include amorphous and/or crystalline forms of, but are not limited to,TiOx, MgO and Al₂O₃.

Moreover, the free layer 816 may be positioned between the referencelayer 815 and the first edge 806.

First and second spacer layers 817, 818 may also be included in thetransducer structure of the thin film region 814 as shown in FIG. 8B.The spacer layers 817, 818 are preferably conductive in some approaches,but may be dielectric in other approaches. The spacer layers 817, 818preferably have a very low ductility, e.g., have a high resistance tobending and deformation in general, and ideally a lower ductility thanrefractory metals such as Ir, Ta, and Ti. The first spacer layer 817 ispositioned between the sensor 809 and the first shield 819 (e.g., theshield closest thereto). Similarly, the second spacer layer 818 ispositioned such that it is sandwiched between the sensor 809 and thesecond shield 820 (e.g., the shield closest thereto).

As shown in FIGS. 8A-8B, tenting may be induced above the sensitivetransducers, thereby minimizing tape-transducer contact in the tentingregion. Particularly, when the tape 802 moves across the head, air isskived from below the tape 802 by the leading edge of the tape supportsurface 824, and though the resulting reduced air pressure in the areabetween the tape 802 and the tape bearing surface 808 allows atmosphericpressure to urge the tape towards the tape bearing surface 808, thecombination of wrap angle and tape bending stiffness causes the tape 802to lift from the tape bearing surface 808 of the module 801 proximate tothe leading edge. Similarly, when the tape 802 moves across the module801, the tape is also lifted from the tape bearing surface 808 proximateto the trailing edge due to the combination of wrap angle α at thetrailing edge and tape bending stiffness. Accordingly, the tentingeffect is bidirectional.

For present purposes, the wrap angle α is measured between a plane 835of the tape bearing surface 808 and a straight line 823 drawn tangent tothe tape supporting surface of the respective guide 862, 860 andintersecting the edge 804. As shown, the tape tends to bow as it wrapsthe edge, and consequently the angle the tape makes relative to theplane 835 of the tape bearing surface 808 at the edge is smaller thanthe wrap angle α.

Any wrap angle α₁ greater than 0° results in a tent 811 being formed bythe tape 802 proximate the leading edge 806 of the tape bearing surface808. A wrap angle α₂ greater than 0° at the trailing edge 804 results ina tent 810 being formed by the tape 802 proximate the trailing edge 804of the tape bearing surface 808. This effect is a function of the wrapangle, tape bending stiffness, tape surface roughness, tape surfacecompressibility, atmospheric pressure, and tape tension, and to a lesserextent, tape speed. For given geometrical wrap angles for example,stiffer tapes tend to produce larger tents 810, 811. Nonetheless, whereconditions such as wrap angle and tape tension are otherwise identical,tapes of a given type from a particular manufacturer tend to exhibit asimilar tenting profile whereby the tenting region defined thereundervaries only slightly from tape to tape. Tapes from differentmanufacturers and/or generations may exhibit dissimilar tentingcharacteristics under otherwise identical conditions. Fortunately,tenting characteristics are readily determinable using numericalmodeling techniques known to those of skill in the art, such as FiniteElement Modeling (FEM), Finite Difference Modeling (FDM), etc. andcombinations thereof. Nonetheless, differences in tentingcharacteristics from tape to tape in the same generation under otherwiseidentical conditions may be considered negligible.

If the wrap angle α₁ is high, the tape 802 will tend to bend awayfurther from the tape bearing surface 808 in spite of the vacuum. Thelarger the wrap angle α₁, the larger the tent 810,811. Ultimately, theforces (atmospheric pressure) urging the tape 802 towards the tapebearing surface 808 may be overcome and the tape 802 becomes decoupledfrom the tape bearing surface 808. Therefore, the wrap angle α₁ ispreferably selected to provide the desired tenting without destroyingthe vacuum induced by skiving. In a preferred embodiment of apparatus800, the wrap angle α₁ created by the guide may be in a range of about0.1 to about 1.5 degrees, but may be higher or lower.

A guide mechanism 860 may be configured to set a wrap angle α₁ of themagnetic recording tape 802 at the first edge 806 of the module 801.Another guide mechanism 862 may be configured to set the wrap angle atthe second edge 804. One or both of such guide mechanisms 860, 862 mayinclude, e.g., a tape guide such as guide 125 of FIG. 1A, a pitchroller, a tension arm, another module, etc. in any combination.

Multiple modules may be assembled to form a tape head having an internalwrap angle that may be selected based on a measurement of theedge-to-sensor separation for each module.

According to the illustrative embodiment in FIG. 8A, the guide mechanism860 may be positioned relative to the first edge 806 at a location thatinduces tenting 811 of a magnetic recording tape 802 moving over themodule 801, where the sensor 809 may be positioned under the location ofthe first tent 811. In some approaches, the guide 860 may be positionedto set a wrap angle of the magnetic recording tape 802 relative to aplane 835 of the tape bearing surface 808. The tape bearing surface 808is shown to be planar, but may be arcuate in other embodiments.

The length of the tape bearing surface 808 may accommodate tape tentingregions 807, 813 along the tape bearing surface 808. The first tapetenting region 813 is generally defined as the region along the tapebearing surface under the tape 802 as the tape 802 forms a tent 811while moving. The second tape tenting region 807 is generally defined asthe region along the tape bearing surface 808 under the tape 802 as thetape 802 forms the tent 810 while moving. Preferably, the two tents 811,810 formed by the tape 802 do not overlap and thus the two tents 811,810 may not interfere with one another.

Furthermore, the module 801 includes a sensor 809 in a thin film region814, where a distance d₁ from the first edge 806 to the sensor 809 maybe less than a distance d₂ from the second edge 804 to the sensor 809.As shown, the sensor 809 may be positioned in the first tape tentingregion 813. Moreover, in some approaches, the distance d₂ from thesecond edge 804 to the sensor 809 may be at least as long as the firsttape tenting region 813.

In some approaches, the first distance d₁ from the first edge 806 to thesensor 809 may be about equal to a second distance d₂ from the secondedge 804 to the sensor 809. Where length d₁ and length d₂ are aboutequal and the wrap angles α₁, α₂ are about the same at both edges 806,804, the sensor 809 within the thin film region 814 may be positioned atabout a peak of the locations of the tenting 811 and 810.

Furthermore, the configuration of the two tenting regions 813, 807 alonga tape bearing surface 808 may include a region 803 where the tape 802may not be subject to significant bending from the edges 804, 806 butrather may be essentially parallel to the tape bearing surface 808.Thus, at the region 803, the tape 802 may be in very close contact withthe tape bearing surface 808.

With continued reference to FIG. 8A, a second guide 862 may bepositioned relative to the second edge 804 for inducing tenting 810 of amoving magnetic recording tape 802, where the first guide 860 positionedrelative to the first edge 806 may be positioned to create a first wrapangle α₁ and the second guide 862 positioned relative to the second edge804 may be positioned to create a second wrap angle α₂, where the firstwrap angle α₁ may not be the same as the second wrap angle α₂, e.g., areat least 0.1 degree different, and preferably greater than about 0.2degrees different. In preferred embodiments, the first wrap angle α₁created by the first guide 860 may be in a range of about 0.1 to about1.5 degrees, but may be higher or lower.

As alluded to above, the second wrap angle α₂ may be at a differentangle than the first wrap angle α₁ to induce tenting having differingcharacteristics, as described in more detail below. In some approaches,the second wrap angle α₂ may be greater than the first wrap angle α₁. Inother approaches, the second wrap angle α₂ may be less than the firstwrap angle α₁, e.g., as shown in FIG. 8A. In another approach, thesecond wrap angle α₂ may be 0, e.g., as shown in FIG. 9, discussedimmediately below.

FIG. 9 depicts an apparatus 850 in accordance with one embodiment. As anoption, the present apparatus 850 may be implemented in conjunction withfeatures from any other embodiment listed herein, such as thosedescribed with reference to the other FIGS. Of course, however, such anapparatus 850 and others presented herein may be used in variousapplications and/or in permutations which may or may not be specificallydescribed in the illustrative embodiments listed herein. Further, theapparatus 850 presented herein may be used in any desired environment.

In one embodiment of apparatus 850 as shown in FIG. 9, the module 851includes a first guide 860 positioned relative to the first edge 806 tocreate a first wrap angle α₁. There is no second wrap angle. There maybe a second guide mechanism 962 in which the tape runs approaches andexits the tape bearing surface adjacent guide 962 without a wrap angle.In some approaches, the first wrap angle α₁ created by the first guide860 may be in a range of about 0.1 to about 1.5 degrees, but could behigher or lower.

Referring once again to FIG. 8B, the guide 860 may be positioned tocreate an inflection point 826 of the moving magnetic recording tape802, the inflection point 826 being at a location above the tape bearingsurface 808 that may be between the free layer 816 and the second edge804. In some embodiments, the free layer 816 may be positioned under theconvex region 828 of the magnetic recording tape 802, as shown in FIG.8B. In other approaches, the free layer 816 may be positioned such thatthe inflection 826 point of the magnetic recording tape 802 is at alocation about directly above the tape bearing surface 808 of the freelayer 816. In yet other approaches, the free layer 816 may be positionedunder the concave region 830 of the magnetic recording tape 802. Inpreferred embodiments, the sensor is under the convex region 828.

In one embodiment of apparatus 800, the sensor 809 may have a referencelayer 815, and a spacer layer 812 positioned between the free layer 816and the reference layer 815. Moreover, the free layer 816 may bepositioned between the reference layer 815 and the first edge 806. Insome approaches, the spacer layer 812 may be a tunnel barrier layer.

FIGS. 10A-10B depict an apparatus 1000 in accordance with oneembodiment. As an option, the present apparatus 1000 may be implementedin conjunction with features from any other embodiment listed herein,such as those described with reference to the other FIGS. Of course,however, such an apparatus 1000 and others presented herein may be usedin various applications and/or in permutations which may or may not bespecifically described in the illustrative embodiments listed herein.Further, the apparatus 1000 presented herein may be used in any desiredenvironment.

As shown, apparatus 1000 includes a module 901 having a tape bearingsurface 808, a first edge of the tape bearing surface 808 forming afirst edge 906, a second edge of the tape bearing surface 808 forming asecond edge 904, where tents 910, 911 formed by the magnetic tape 902may extend from the edges 904, 906 along the tape bearing surface 808. Asensor 909 is positioned in a thin film region 914 of the module 901.Moreover, the sensor 909 includes a free layer.

Furthermore, the distance d₁ from the first edge 906 along the tapebearing surface 808 of the free layer of the sensor 909 may be less thana distance d₂ from the second edge 904 to the free layer of the sensor909.

In other approaches of apparatus 1000, a media facing side of the sensor909 may be recessed from the tape bearing surface 808.

In an exemplary embodiment, e.g., as shown in FIG. 10, the module 901includes a wear coating 917 on a media facing side of the sensor 909where a peak height h may be defined between a peak of the tenting 911and an upper surface 921 of the coating 917. The thickness the of thecoating 917 may be defined by the distance between the upper surface 919of th_(c) tape support surface 922, 924 and the upper surface 921 of thecoating 917. In some approaches, the thickness th_(c) of the coating 917may be in a range of between about 0.5 and about 3 times the peak heighth. For example, FIG. 10B illustrates a thickness th_(c) of a coating 917that may be about two times the peak height h.

In yet another approach of apparatus 1000, the guide may be a secondmodule having magnetic transducers thereon such as one of the othermodules, e.g., as shown in the various FIGS. (see FIG. 6 with twomodules and FIG. 7 with three modules).

One embodiment of apparatus 1000 may include a drive mechanism such as amotor or other known mechanism that is configured to cause the tape tomove over the first block and a controller electrically coupled to thedrive mechanism. For example, the motor or other known mechanism maydrive a tape supply cartridge, e.g., tape supply cartridge 120 of FIG.1A, and a take-up reel, e.g., take-up reel 121 also of FIG. 1A, of adrive in which the block is implemented in, to move the tape media overthe block and/or other components of the drive.

FIGS. 11A-11B represent modeling examples from a Finite Element Modeling(FEM) technique that shows how the wear on the module by the runningtape may change the tape profile as the tape head becomes worn. Thex-axis shows the distances between the edges of the modules in the twomodels (0 to 225 μm on the x-axis in FIG. 11A, and 0 to 125 μm on thex-axis in FIG. 11B) with the sensor placed nearest the edge on the leftof the head. Preferably, the free layer of the sensor is positionedbetween the tunnel barrier layer and the first edge in order to mitigateshorting across the TMR sensor.

In the modeling examples of FIGS. 11A and 11B, the y-axis shows theheight of the tape and the tenting profile above the module. The uppersurface of the coating is indicated by 0 thereby representing the tapebearing surface. The substrate, sensor, and closure show an uppersurface (below the coating) at approximately −15 nm on the y-axis. Eachfigure (FIGS. 11A and 11B) shows the tape profile modeling for differentextents of wear of the tape bearing surface, either tape an unworn headwith coating (thick black line), or tape over a worn head with coating(thin black line).

FIG. 11A illustrates the modeling wear simulations of a preferredembodiment. Wear near the center of the module is indicated by a slightdip in the upper surface of the coating along the 0 marker of they-axis. At the edges of the closure and substrate, there is minimal wearsince conventional modern tapes are less likely to wear the hard ceramicmaterial of the substrate and closure (the bottom portion −20 and −15 nmon the y-axis). Running the tape over the module will generally causethe coatings to wear, especially at the edges and to a smaller extent inthe center of the module (shown in FIG. 11A at the edges of the coatingportion, at the 0 on the y-axis). This pattern of head wear may even beseen with very durable coatings.

Wear of the coating slows significantly or effectively stops when thetape begins to contact the edges of the ceramic of the head at thesubstrate and closure. At this level of wear on the module, the coatingtends to acquire a bevel. With continued reference to FIG. 11A,comparing the tape profile of the tape run over an unworn head (thickblack line) and the tape run over a worn head (thin black line), it wassurprising and unexpected that the tape-to-head spacing above the sensorremained essentially unchanged, thereby suggesting that the spacing wasunaffected by the wear.

Furthermore, the region of the tape having a convex curvature (asopposed to a flatter shape at the inflection point) tended to movetowards the sensor position. Thus, without wishing to be bound by anytheory, the inventor believes that having a thick durable coating givesthe surprising benefit that as the coating slowly wears, the curvatureof the tape above the sensors may change to a convex shape but may notincrease in head-to-tape spacing. In other words, on a coated head, theconvex region may move into a desired location above the sensors wherethe coating is approximately twice as thick as the magnetic head-to-tapespacing (as illustrated in FIG. 10B). In contrast, on the uncoated head,the convex region created by the tape may be closer to the edge andtherefore may tend to have higher spacing. Coatings with intermediatethicknesses may produce results in between these two cases.

FIG. 11B illustrates the modeling wear simulation in an embodiment wherethe land length is significantly shorter (125 μm) than the embodimentshown in FIG. 11A (225 μm). In addition, the wrap angle on the right isrelatively large, 0.9 degrees. This embodiment shows that positioningthe sensor asymmetrically (towards the first edge of the head) may becombined with a narrow land and asymmetrical wrap angles and large wrapangles. The smaller land with increased wrap angle may result in thetents formed by the tape between the two edges colliding together andthus the length between the tents may not flatten above the module.

The simulation shown in FIG. 11B also demonstrates the surprising andunexpected result that the head-to-tape spacing proximate to the sensormay not be notably affected by wear when the sensor is positionedasymmetrically near one edge. In contrast, the inventor had expectedthat the absence of a flattened portion of the tape near the center ofthe module would result in greater head-to-tape spacing above the sensorin the tenting region. Surprisingly, the opposite effect was observed.

Without wishing to be bound by any theory, it appears that anysensitivity to changes with wear may not be dependent on starting shapeof the module or wrap angles. Thus, there are advantages to this design.Namely, the asymmetrical head geometry may accommodate variations intape and head design. Moreover, the wrap angle on the distant edge(second edge) may be adjusted to help stiffen the tape profile alongwith narrowing the land. In turn, stiffening the tape may improveflutter and help mitigate shorting.

Moreover, as demonstrated by FIG. 11B, the tenting regions may overlap.One way of controlling the amount of overlap without significantlychanging the height of the tape above the transducer is to control thesecond wrap angle at the second edge. This may provide additionalbending stiffness in the tape between the peaks, which may reduce tapejitter and may improve signal quality. This may also be facilitated bymaking the distance between the two edges smaller.

FIG. 12 depicts a method 1200 for determining a wrap angle to induce adesired tenting in accordance with one embodiment. As an option, thepresent method 1200 may be implemented in conjunction with features fromany other embodiment listed herein, such as those described withreference to the other FIGS. Of course, however, such a method 1200 andothers presented herein may be used in various applications and/or inpermutations which may or may not be specifically described in theillustrative embodiments listed herein. Further, the method 1200presented herein may be used in any desired environment.

According to one embodiment as shown in FIG. 12, method 1200 includes astep 1202 of determining a distance from a first edge to a sensor of amodule. Looking to FIG. 8B which represents the circle 8B in FIG. 8A, adistance d₁ may represent the length of the portion between the edge 806and the sensor 809. As illustrated in FIG. 8B, the media bearingsurfaces 808 of the module 801 may be primarily planar. In embodimentswhere the media bearing surface 808 of the module 801 is primarilyplanar, the planar portions of the media bearing surface 808 may liealong a common plane 835.

In one embodiment, the distance d₁ is a stored value that is retrieved.In another embodiment, the distance d₁ is detected. In some approaches,the distance d₁, from first edge 806 to sensor 809, and/or the distanced₂ from the second edge 804 to the sensor 809, may be measuredmechanically using conventional techniques. For example, atomic forcemicroscopy and/or stylus profilometry may be used. In other approaches,the distance d₁ and/or distance d₂ may be measured optically usingconventional techniques. For example, machine vision may be used. In oneapproach, laser or other optical interferometry may be used. Preferably,the resolution of the optical detector is in the sub-micron level. Themodule may have a distance d₁ from edge 806 to sensor 809, of less than100 μm in order for the module to be wide enough for accuratepositioning of the guide to determine a wrap angle α₁.

With continued reference to FIG. 12, method 1200 includes a step 1204 ofselecting a first wrap angle based on the detected distance for inducingtenting of a magnetic recording tape in a region above the sensor whenthe magnetic recording tape moves over the module. For example, lookingto FIG. 8B a wrap angle α₁ may be selected based on the distance d₁ forinducing a tenting of a magnetic recording tape 802 in a region (e.g.region of tenting 811) above the sensor 809 when the magnetic recordingtape 802 moves across the module.

In various embodiments of method 1200, the wrap angle may be selectedbased on one or more desired tenting characteristics that are variablewith changing wrap angle.

One such tenting characteristic is peak height of the tenting formed ata particular wrap angle α₁. See, e.g., peak height h of a tent 811 inFIG. 8B. Another tenting characteristic is tent height h_(m) directlyabove the transducer. In some approaches, the peak height h and/or tentheight h_(m) may be in a range of from about 5 to about 30 nanometersfrom a media bearing surface 808 of media support surface 824, but couldbe higher or lower. In various approaches, the peak height h and/or tentheight h_(m) may be measured from the plane of the media facing surfaceof a sensor or from the media facing surface of a sensor that isrecessed from the plane of the tape support surface (see FIGS. 10A and10B).

In some approaches, the tenting characteristic may be a length of a tent811 formed at a particular wrap angle α₁.

Tenting characteristics corresponding to differing wrap angles may bedetermined experimentally, e.g., by running a tape over the module andmeasuring characteristics; determined via modeling; extrapolated fromexperimental or modeled data; etc. Tenting characteristics may beapproximated and/or averaged across several different types of tapesthat are compatible with the module to select a wrap angle that is abest fit for all types of tape. In some approaches, the wrap angle maybe selected under an assumption that the tenting characteristics of alltapes suitable for use with the module behave in a substantially similarmanner and therefore any commercially-available tape may be used inexperimentation or modeling to determine the tenting characteristics.

In another approach, wrap angles may be calculated for each of aplurality of magnetic recording tapes from different manufacturers tocreate a similar desired tent region above the tape bearing surface ofthe sensor. The results can be stored in a table and applied when eachparticular tape is detected by the drive.

Whichever approach is used to determine a wrap angle, the determinedwrap angle(s) may be output, e.g., for use in positioning components ofa tape drive for creating the desired wrap angle.

With continued reference to FIG. 12, method 1200 includes a step 1206 ofdetermining a distance from a second edge to a sensor of a module.Looking to FIG. 8A, a distance d₂ may represent the length of theportion between the second edge 804 and the sensor 809. The mediabearing surfaces 808 of the module 801 may be primarily planar. Inembodiments where the media bearing surface 808 of the module 801 isprimarily planar, the planar portions of the media bearing surface 808may lie along a common plane 835.

With continued reference to FIG. 12, method 1200 includes a step 1208 ofselecting a second wrap angle based on the detected distance forinducing tenting of a magnetic recording tape in a region above thesensor when the magnetic recording tape moves over the module. Forexample, looking to FIG. 8A a wrap angle α₂ may be selected based on thedistance d₂ for affecting or not affecting the tenting of the magneticrecording tape 802 in a region (e.g. region of tenting 811) above thesensor 809 when the magnetic recording tape 802 moves across the module.The second wrap angle on the α₂ may be selected to further adjust theheight of the tape tent, or to have no effect at all.

In various embodiments of method 1200, the wrap angle may be selectedbased on one or more tenting characteristics that vary with changingwrap angle.

In one embodiment of method 1200, consideration may be given to whetherthe wrap angles are to be set using a second module. If so, thenpositioning a second module may be used to set the selected wrap angle.If not, positioning a guide may be used to set the selected wrap angle.

In some approaches, one or both of the wrap angles α₁,α₂ may be set inthe drive by dynamic guides. One approach employs eccentric rollers,whereby the offset axis creates an orbital arc of rotation, allowingprecise alignment of the wrap angles α₁,α₂. Alternatively, outriggers ofa type known in the art may be used to set the wrap angles α₁,α₂.

In some embodiments, the wrap angles α₁,α₂ may be dynamically set in thedrive. In one approach, a dynamically-positionable tape head may be usedwith fixed rollers. In another approach, the wrap angles α₁,α₂ may beset by a positionable tape support within the drive. Following method1200 in which the distance of the sensor to the edge closest thereto ismeasured and may be used to determine the wrap angle at a givensensor-to-tape spacing, the tape guide may be adjusted to set thedesired wrap angle.

Magnetic recording tapes from different manufacturers may performdifferently as the tape runs over the edge. Thus, different wrap anglesmay be calculated for magnetic recording tapes from differentmanufacturers to create a similar desired tent region above the tapebearing surface of the sensor. Various embodiments described hereinprovide a method to determine a wrap angle for a magnetic recording tapeover a sensor.

FIG. 13 depicts a method 1300 in accordance with one embodiment. As anoption, the present method 1300 may be implemented in conjunction withfeatures from any other embodiment listed herein, such as thosedescribed with reference to the other FIGS. Of course, however, such amethod 1300 and others presented herein may be used in variousapplications and/or in permutations which may or may not be specificallydescribed in the illustrative embodiments listed herein. Further, themethod 1300 presented herein may be used in any desired environment.

As shown in FIG. 13, in one embodiment of method 1300, step 1302includes running a magnetic recording tape over an edge adjacent asensor of a module.

Step 1304 of method 1300 involves detecting magnetic fields from thetape e.g., data, where an extent of spacing is detectable as spacingloss, and representative of the distance at differing wrap angles of thetape over the edge for a height of tenting of the tape above the sensor.

Step 1306 of method 1300 includes selecting one of the wrap angles toprovide about a desired height of tenting of the tape above the sensor.In preferred embodiments, the portion of the tape directly above thesensor is convex. See, e.g., FIG. 11A.

In some approaches, method 1300 may involve positioning a second moduleto set the selected wrap angle. In other approaches, method 1300 mayinvolve positioning a guide to set the selected wrap angle.

In some approaches to method 1300, the wrap angle may be selected basedon a tenting characteristic that varies with changing wrap angle. Inother approaches, the tenting characteristic may be a peak height of atent formed at a particular wrap angle. In yet other approaches, thepeak height may be in a range of from about 5 to about 30 nanometersfrom a media facing side of the transducer.

In another embodiment of method 1300 the tenting characteristic may be alength of a tent formed at a particular wrap angle.

Now referring to FIG. 14, a flowchart of a method 1400 is shownaccording to one embodiment. The method 1400 may be performed inaccordance with the present invention in any of the environmentsdepicted in FIGS. 1-12, among others, in various embodiments. Of course,more or less operations than those specifically described in FIG. 14 maybe included in method 1400, as would be understood by one of skill inthe art upon reading the present descriptions.

Each of the steps of the method 1400 may be performed by any suitablecomponent of the operating environment. For example, in variousembodiments, the method 1400 may be partially or entirely performed by acontroller, a processor, a tape drive, or some other device having oneor more processors therein. The processor, e.g., processing circuit(s),chip(s), and/or module(s) implemented in hardware and/or software, andpreferably having at least one hardware component, may be utilized inany device to perform one or more steps of the method 1400. Illustrativeprocessors include, but are not limited to, a CPU, an ASIC, a FPGA,etc., combinations thereof, or any other suitable computing device knownin the art.

As shown in FIG. 14, method 1400 may initiate with operation 1402 wherethe processor receives a measurement of the distance from a first edgeto a sensor. The distance may be measured optically, such as usingautocollimators and/or laser focusing. In other approaches, the distancemay be measured mechanically.

Method 1400 may proceed with operation 1404 in which the processorreceives a predefined height of tenting of a magnetic recording tapeabove the sensor.

Method 1400 includes operation 1406 where the processor calculates thewrap angle when the magnetic recording tape moves over the module.

In some embodiments of method 1400, a module of a tape head may beadjusted in a vertical direction to create the calculated wrap anglewhen the magnetic recording tape moves over the module.

In other embodiments of method 1400, a guide may be set to create thecalculated wrap angle of the magnetic recording tape.

The present invention may be a system, a method, and/or a computerprogram product. The computer program product may include a computerreadable storage medium (or media) having computer readable programinstructions thereon for causing a processor to carry out aspects of thepresent invention.

The computer readable storage medium can be a tangible device that canretain and store instructions for use by an instruction executiondevice. The computer readable storage medium may be, for example, but isnot limited to, an electronic storage device, a magnetic storage device,an optical storage device, an electromagnetic storage device, asemiconductor storage device, or any suitable combination of theforegoing. A non-exhaustive list of more specific examples of thecomputer readable storage medium includes the following: a portablecomputer diskette, a hard disk, a random access memory (RAM), aread-only memory (ROM), an erasable programmable read-only memory (EPROMor Flash memory), a static random access memory (SRAM), a portablecompact disc read-only memory (CD-ROM), a digital versatile disk (DVD),a memory stick, a floppy disk, a mechanically encoded device such aspunch-cards or raised structures in a groove having instructionsrecorded thereon, and any suitable combination of the foregoing. Acomputer readable storage medium, as used herein, is not to be construedas being transitory signals per se, such as radio waves or other freelypropagating electromagnetic waves, electromagnetic waves propagatingthrough a waveguide or other transmission media (e.g., light pulsespassing through a fiber-optic cable), or electrical signals transmittedthrough a wire.

Computer readable program instructions described herein can bedownloaded to respective computing/processing devices from a computerreadable storage medium or to an external computer or external storagedevice via a network, for example, the Internet, a local area network, awide area network and/or a wireless network. The network may comprisecopper transmission cables, optical transmission fibers, wirelesstransmission, routers, firewalls, switches, gateway computers and/oredge servers. A network adapter card or network interface in eachcomputing/processing device receives computer readable programinstructions from the network and forwards the computer readable programinstructions for storage in a computer readable storage medium withinthe respective computing/processing device.

Computer readable program instructions for carrying out operations ofthe present invention may be assembler instructions,instruction-set-architecture (ISA) instructions, machine instructions,machine dependent instructions, microcode, firmware instructions,state-setting data, or either source code or object code written in anycombination of one or more programming languages, including an objectoriented programming language such as Smalltalk, C++ or the like, andconventional procedural programming languages, such as the “C”programming language or similar programming languages. The computerreadable program instructions may execute entirely on the user'scomputer, partly on the user's computer, as a stand-alone softwarepackage, partly on the user's computer and partly on a remote computeror entirely on the remote computer or server. In the latter scenario,the remote computer may be connected to the user's computer through anytype of network, including a local area network (LAN) or a wide areanetwork (WAN), or the connection may be made to an external computer(for example, through the Internet using an Internet Service Provider).In some embodiments, electronic circuitry including, for example,programmable logic circuitry, field-programmable gate arrays (FPGA), orprogrammable logic arrays (PLA) may execute the computer readableprogram instructions by utilizing state information of the computerreadable program instructions to personalize the electronic circuitry,in order to perform aspects of the present invention.

Aspects of the present invention are described herein with reference toflowchart illustrations and/or block diagrams of methods, apparatus(systems), and computer program products according to embodiments of theinvention. It will be understood that each block of the flowchartillustrations and/or block diagrams, and combinations of blocks in theflowchart illustrations and/or block diagrams, can be implemented bycomputer readable program instructions.

These computer readable program instructions may be provided to aprocessor of a general purpose computer, special purpose computer, orother programmable data processing apparatus to produce a machine, suchthat the instructions, which execute via the processor of the computeror other programmable data processing apparatus, create means forimplementing the functions/acts specified in the flowchart and/or blockdiagram block or blocks. These computer readable program instructionsmay also be stored in a computer readable storage medium that can directa computer, a programmable data processing apparatus, and/or otherdevices to function in a particular manner, such that the computerreadable storage medium having instructions stored therein comprises anarticle of manufacture including instructions which implement aspects ofthe function/act specified in the flowchart and/or block diagram blockor blocks.

The computer readable program instructions may also be loaded onto acomputer, other programmable data processing apparatus, or other deviceto cause a series of operational steps to be performed on the computer,other programmable apparatus or other device to produce a computerimplemented process, such that the instructions which execute on thecomputer, other programmable apparatus, or other device implement thefunctions/acts specified in the flowchart and/or block diagram block orblocks.

The flowchart and block diagrams in the Figures illustrate thearchitecture, functionality, and operation of possible implementationsof systems, methods, and computer program products according to variousembodiments of the present invention. In this regard, each block in theflowchart or block diagrams may represent a module, segment, or portionof instructions, which comprises one or more executable instructions forimplementing the specified logical function(s). In some alternativeimplementations, the functions noted in the block may occur out of theorder noted in the figures. For example, two blocks shown in successionmay, in fact, be executed substantially concurrently, or the blocks maysometimes be executed in the reverse order, depending upon thefunctionality involved. It will also be noted that each block of theblock diagrams and/or flowchart illustration, and combinations of blocksin the block diagrams and/or flowchart illustration, can be implementedby special purpose hardware-based systems that perform the specifiedfunctions or acts or carry out combinations of special purpose hardwareand computer instructions.

Moreover, a system according to various embodiments may include aprocessor and logic integrated with and/or executable by the processor,the logic being configured to perform one or more of the process stepsrecited herein. By integrated with, what is meant is that the processorhas logic embedded therewith as hardware logic, such as an applicationspecific integrated circuit (ASIC), a field programmable gate array(FPGA), etc. By executable by the processor, what is meant is that thelogic is hardware logic; software logic such as firmware, part of anoperating system, part of an application program; etc., or somecombination of hardware and software logic that is accessible by theprocessor and configured to cause the processor to perform somefunctionality upon execution by the processor. Software logic may bestored on local and/or remote memory of any memory type, as known in theart. Any processor known in the art may be used, such as a softwareprocessor module and/or a hardware processor such as an ASIC, a FPGA, acentral processing unit (CPU), an integrated circuit (IC), etc.

It will be clear that the various features of the foregoing systemsand/or methodologies may be combined in any way, creating a plurality ofcombinations from the descriptions presented above.

It will be further appreciated that embodiments of the present inventionmay be provided in the form of a service deployed on behalf of acustomer.

The inventive concepts disclosed herein have been presented by way ofexample to illustrate the myriad features thereof in a plurality ofillustrative scenarios, embodiments, and/or implementations. It shouldbe appreciated that the concepts generally disclosed are to beconsidered as modular, and may be implemented in any combination,permutation, or synthesis thereof. In addition, any modification,alteration, or equivalent of the presently disclosed features,functions, and concepts that would be appreciated by a person havingordinary skill in the art upon reading the instant descriptions shouldalso be considered within the scope of this disclosure.

While various embodiments have been described above, it should beunderstood that they have been presented by way of example only, and notlimitation. Thus, the breadth and scope of an embodiment of the presentinvention should not be limited by any of the above-described exemplaryembodiments, but should be defined only in accordance with the followingclaims and their equivalents.

1. An apparatus, comprising: a module having a tape bearing surface, afirst edge, and a second edge, wherein a tape tenting region of the tapebearing surface extends from the first edge along the tape bearingsurface toward the second edge, the first edge of the tape bearingsurface being a first end of the tape tenting region, a second end ofthe tape tenting region being positioned between the first and secondedges; a guide positioned relative to the first edge for inducingtenting of a moving magnetic recording tape, wherein a location of thetenting is above an entirety of the tape tenting region, wherein thesecond end of the tape tenting region is located at a location where thetenting terminates at a point of closest approach of the tape to thetape bearing surface after a peak of the tenting; and a transducerpositioned in the tape tenting region, wherein the module has a wearcoating on a media facing side of the transducer, wherein a peak heightis defined between the peak of tenting and an upper surface of thecoating, wherein a thickness of the coating is in a range of betweenabout 0.5 and about 3 times the peak height.
 2. An apparatus as recitedin claim 1, wherein the guide positioned relative to the first edge ispositioned to create a wrap angle and there is no second wrap angle. 3.An apparatus as recited in claim 2, wherein the wrap angle created bythe guide is in a range of about 0.1 to about 1.5 degrees.
 4. Anapparatus as recited in claim 1, comprising a second guide positionedrelative to the second edge for inducing tenting of a moving magneticrecording tape, wherein the guide positioned relative to the first edgeis positioned to create a first wrap angle and the second guide ispositioned relative to the second edge to create a second wrap angle. 5.An apparatus as recited in claim 4, wherein the first wrap angle is notthe same as the second wrap angle.
 6. An apparatus as recited in claim4, wherein the second wrap angle is greater than the first wrap angle.7. An apparatus as recited in claim 4, wherein the second wrap angle isless than the first wrap angle.
 8. An apparatus as recited in claim 1,wherein the guide is positioned to create an inflection point of themoving magnetic recording tape at a location above the tape tentingregion of the tape bearing surface that is between the transducer andthe second edge.
 9. An apparatus as recited in claim 1, wherein thetransducer is a TMR sensor.
 10. An apparatus as recited in claim 1,wherein the tape bearing surface is planar.
 11. An apparatus as recitedin claim 1, wherein a distance from the second edge to the transducer isat least as long as the tape tenting region.
 12. An apparatus as recitedin claim 1, comprising a wear coating on a media facing side of thetransducer, wherein a peak height is defined between a peak of a tapetent and an upper surface of the coating, wherein a thickness of thecoating is in a range of between about 0.5 and about 3 times the peakheight.
 13. An apparatus as recited in claim 1, wherein a media facingside of the transducer is recessed from the tape bearing surface.
 14. Anapparatus as recited in claim 1, further comprising: a drive mechanismfor moving a magnetic medium over the module; and a controllerelectrically coupled to the transducer. 15.-24. (canceled)